Cobalt carbonato

Table 2. Some copp>er and cobalt carbonato complexes and the corresponding IR absorption bands related to CO32- vibrations, vi, V2 and V4 correspond to vibrations of CO32- in the C2v symmetry notation according to this notation, the doubly degenerate V3 vibration of the free CCh - ion, which splits into two components, is denoted as vi and V4, whereas the activated Vi vibration is denoted as V2 (data compiled from Gatehouse et al., 1958 Fujita et al., 1962 Jolivet et al., 1982 Healy White, 1972).

Diaqu o - tetrammino - cobaltic Chloride, [Co(NHs)4.(H20)2]C13.— The salt has been obtained water free as above or containing one molecule of water, [Co(NH3)4.(H20)2]Cl3.IT2Q. This salt is also prepared from the carbonato-salt by dissolving it in water containing a little hydrochloric acid. The liquid is then cooled in ice and the diaquo-tetrammino-cobaltic chloride precipitated by the addition of concentrated hydrochloric acid. It is filtered off, washed with acid, then with 95 per cent, alcohol, and dried in air. 

Aquo - derivatives of nitrato - pentammino - salts are known. For example, nitrato-aquo-tetrammino-cobaltic nitrate, [Co(NH3)4 (H20)(X03)](X03)2, is prepared from carbonato-tetranunino-eobaltic nitrate, [Co(XH3).1(C03)]N03,a by treating it in aqueous solution with concentrated nitric acid, when the aquo-salt is precipitated. 

Dibromo-tetrammino-cobaltic Bromide, [Co(NH3)4Bra] Br, is prepared from carbonato-tetrammino-eobaltic bromide by acting upon it with fuming hydrobromic acid, when the following reaction takes place —... 

The m-position is assigned to the carbonato-series, and this seems to be supported by the experimental evidence. Only one series of salts has been prepared, and these salts have been used in the determination of the configuration of the diacido-tetrammino-cobaltic salts. Thus, earbonato-tetrammino-cobaltie salts when treated with acid and sodium nitrite yield m-dinitro-tetrammino-salts. The reaction may be formulated ... 

Carbonato-tetrammino-cobaltic Nitrate, [Co(NH3)4C03]N03. i-H20, is prepared in the same -way as the sulphate by the action of nitric acid on cobaltous carbonate. It crystallises in glistening carmine-red rhombic plates and dissolves in water, giving a deep red solution. The crystals lose water at 100° C., but take up water again on standing in air. 

Oxalato-tetrammino-cobaltic Salts, [Co(NH3)4(C204)]R.—These salts are analogous to the carbonato-salts, and were first described by Jorgensen in 1894. 

Synthesis of carbonato tetraamine cobalt (III) nitrate (CTCN) by Schlessing-er s method [243]. 

These equations are in line with Eq. (30), such that kx denotes the ring-opening rate constant of the protonated carbonato complex and / 2 is the decarboxylation rate constant of the ring-opened bicarbonato complex. Values of these rate constants and the acid dissociation constants of some protonated carbonato complexes of cobalt(TII) (see Table III) reflect the ligand dependence with respect to charge variations, steric constraint, and donor properties of the non-labile ligands. 

In certain instances, the coordinated oxygen atom may undergo reaction. The complete and elegant work carried out on carbonato-ammine complexes of cobalt (III) illustrates this situation. As Equation 34 reveals, the acid hydrolysis of [ (NH3)5CoC03]+ involves substitution at the carbon-oxygen bond, rather than the cobalt-oxygen bond (4). 

In the following, a series of preparations of dianionobis(ethyl-enediamine)cobalt(III) compounds, all starting with (carbonato)-bis(ethylenediamine)cobalt(III) chloride are given. (Carbonato )bis-(ethylenediamine)cobalt(III) chloride has been prepared with a high yield (80%) by a new method based upon the use of cobalt(II) chloride and the equivalent amount of (2-aminoethyl)-carbamic acid. The carbonato compound is easily converted into a number of dianionobis(ethylenediamine)cobalt(III) compounds with high yields. In some of the following procedures it was possible to use the carbon dioxide-ethylenediamine reaction mixture directly. 

Besides (carbonato)bis(ethylenediamine)cobalt(III) chloride and the corresponding bromide salt, the following complexes are described cis- and frara -dichlorobis(ethylenediamine)cobalt(III) chloride, cts-aquachlorobis(ethylenediamine)cobalt(III) sulfate, cis-bis(ethylenediamine)dinitrocobalt(III) nitrite, m-aquabis-(ethylenediamine)hydroxocobalt(III) dithionate, and cis-diaqua-bis(ethylenediamine)cobalt(III) bromide. 

The following procedure is based on the reaction of an aqueous solution of cobalt(II) chloride with the equivalent amount of (2-aminoethyl)carbamic acid, followed by oxidation with hydrogen peroxide and the subsequent formation of bis(ethylene-diamine)cobalt(III) ions. The bis(ethylenediamine)cobalt(lII) species are converted to the carbonato complex by reaction with lithium hydroxide and carbon dioxide. During the entire preparation a vigorous stream of carbon dioxide is bubbled through the reaction mixture. This procedure appears to be essential in order to minimize the formation of tris(ethylenediamine)cobalt(III) chloride as a by-product. However, the formation of a negligible amount of the tris salt cannot be avoided. The crude salts have a purity suitable for preparative purposes. The pure salts are obtained by recrystallization from aqueous solution. 

An aqueous solution of the (carbonato)bis(ethylenediamine)-cobalt(III) ion is rather stable.3 The visible absorption spectrum of... 

The traditional method of isolating the trans-dichlorobis-(ethylenediamine)cobalt(III) chloride salt by evaporation of the reaction mixture to dryness in the steam bath gives some reduction to cobalt(II). To avoid this, the chloride salt in the following procedure is isolated by saturation of the reaction mixture with hydrogen chloride gas and by precipitation with standing at room temperature. As an alternative method, the reaction mixture from the preparation of (carbonato)bis(ethylene-diamine)cobalt(III) chloride can be used as the starting material. 

Preparation from (Carbonato)bis(ethylenediainine)cobalt(III) Chloride... 

To 27.5 g. (0.1 mole) of crude (carbonato)bis(ethylenediamine)-cobalt(III) chloride is added 200 ml. of 1.00 N hydrochloric acid. The carbonato complex is dissolved with evolution of carbon dioxide gas and formation of a red solution consisting primarily of the corresponding cw-diaqua species. The solution is evaporated in the steam bath until an almost dry paste has been formed. The purple residue is filtered and washed with three 20-ml. portions of ice-cold water. Drying in air yields 19.5 g. of purple crystals of cu-dichlorobis(ethylenediamine)cobalt(III) chloride. The mother liquor and the washings are again evaporated almost to dryness to yield a second crop of crystals, 5.9 g. The total yield is 25.4 g. (84% based on (carbonato)bis(ethylenediamine)cobalt(III) chloride). The analysis and the visible absorption spectrum of the two fractions are identical. Anal. Calcd. for [Co(en)2Cl2 ] C1 H20 Co, 19.42 N, 18.46 C, 15.82 Cl, 35.05 H, 5.98. Found Co, 19.50 N, 18.57 C, 15.77 C1, 35.15 H, 6.01. 

A 137.3-g. (0.5-mole) sample of crude (carbonato)bis(ethyl-enediamine)cobalt(III) chloride is added with stirring to 275 ml. of 4 M hydrochloric acid cooled to 0-5°C. in an ice bath. The... 

Disodium cw-bis(ethylenediamine)disuIfitocobaltate(III) nitrate and also the perchlorate have not been reported before and are recommended as sources of the cfs-bis(ethylenediamine)disulfito-cobaltate(III) ion, which has been prepared by Baldwin1 by proceeding through a difficult series of complex salts. The m-azidobis(ethylenediamine)sulfitocobalt(III) is also newly reported it can be converted into a relatively pure sodium ran.y-bis(ethylenediamine)disulfitocobaltate(III), which has previously been made from dichlorobis(ethylenediamine)cobalt(III) chloride1 and tetraammine(carbonato)cobalt(III) chloride.2... 

Menif, R. Reibenspies, J. Martell, A. E. Synthesis, protonation constants, and copper(II) and cobalt(II) binding constants of a new octaaza macrobicylic cryptand (MX)3crystal structures of the cryptand and of the carbonato-bridged dinuclear copper(II) cryptate, Inorg. Chem. 1991, 30, 3446-3454. 

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